(ii) techniques and procedures used to investigate the motion and collisions of objects
(b) (i) acceleration g of free fall
(ii) techniques and procedures used to determine the acceleration of free fall using trapdoor and electromagnet arrangement or light gates and timer
(c) reaction time and thinking distance; braking distance and stopping distance for a vehicle.

(a) drag as the frictional force experienced by an object travelling through a fluid
(b) factors affecting drag for an object travelling through air
(c) motion of objects falling in a uniform gravitational field in the presence of drag
(d) (i) terminal velocity
(ii) techniques and procedures used to determine terminal velocity in fluids.

(a) density;
(b) pressure; for solids, liquids and gases
(c) ; upthrust on an object in a fluid; Archimedes’ principle.

3.3 Work, energy and power

3.3.1 Work and conservation of energy

(a) work done by a force; the unit joule
(b) for work done by a force
(c) the principle of conservation of energy
(d) energy in different forms; transfer and conservation
(e) transfer of energy is equal to work done.

3.3.2 Kinetic energy and potential energies

(a) kinetic energy of an object;
(b) gravitational potential energy of an object in a uniform gravitational field;
(c) the exchange between gravitational potential energy and kinetic energy.